Such a piston arrangement is known from U.S. Pat. No. 4,070,122. On the end next to the piston, the connecting rod has a ball cup, in which the ball is inserted, being fixed at the piston head by means of a rivet. Oil flowing through the oil supply channel is then able to lubricate the contact face between the ball cup and the ball. Exactly like the piston arrangement of the present invention, the known piston arrangement is meant for use with refrigerant compressors.
JP 55-148985 A shows a further piston arrangement, in which the ball is located at the end of the connecting rod and made in one piece with the connecting rod. The oil supply channel does not only penetrate the connecting rod, but also the ball, and is connected with grooves, which are located on the surface of the ball. Through these grooves, lubricating oil can be distributed evenly in the bearing surface between the ball and the ball cup.
JP 56-012073 shows a piston arrangement, in which the ball is also made in one piece with the connecting rod. The connecting rod has a stepped oil supply channel, which expands in the direction of the piston. The steps are intended to hold the oil back during a compression stroke.
U.S. Pat. No. 6,006,652 shows a ball joint in a piston arrangement of a refrigerant compressor, in which the ball is held in a ball cup, whose end facing the connecting rod is bordered on the ball. An oil supply to the bearing surface takes place from the compression chamber through openings in the piston head or the piston skirt, respectively.
U.S. Pat. No. 4,913,001 shows a piston arrangement with a ball joint, in which the ball is also held in the ball cup by bordering a part of the piston head. In the area of the bordering, the ball cup has lateral openings, through which oil, which is sprayed into the inside of the piston, can flow to or from the ball joint, respectively.
U.S. Pat. No. 5,137,431 shows a further refrigerant compressor with a piston arrangement, whose ball joint is supplied with oil via a channel branching off from a gap between the piston skirt and the inner wall of the cylinder, in which the piston is moving.
It is an object of the present invention to improve upon or overcome the problems associated with the prior art.